A New Productivity Prediction Model for Multi-fractured Horizontal Wells in Tight Oil Reservoirs

Abstract The productivity of Multi-fractured horizontal wells (MFHWs) in the tight oil reservoirs is the key index to evaluate the effect of volume fracturing. In this study, to find a solution for this problem, firstly, the big data affecting the productivity of MFHWs were collected, and then a multi-level evaluation system was built by using the analytic hierarchy process(AHP). Secondly, the gray theory was used to calculate the correlation coefficients between different parameters and production capacity to screen out the key parameters affecting the production capacity. Finally, a new horizontal well productivity prediction model by coupling key geological and engineering parameters was established, to calculate the similarity coefficient and realize quantitative prediction of single well productivity. The results show that the length of horizontal section, formation pressure, fracturing fluid volume, number of stages, net pay thickness and permeability are the key parameters affecting productivity of MFHWs. The new productivity prediction model has been successfully applied to 175 wells in China’s typical tight oil fields, with prediction errors less than 5%. It can be used in productivity prediction of horizontal wells after volume fracturing in similar unconventional tight oil reservoirs, has broad application prospects, and can guide the efficient development of and fracturing scheme selection for tight oil reservoirs effectively.